Circuit interrupter



Sept. 1939. G. N. LEMMON 2,172,143

CIRCUIT INTERRUPTER Original Filed Nov. 9, 1936 Patentedl Sept. 5, 1939UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER mingham, Ala.

Application November Renewed 9 Claims.

This invention relates to the type of circuit interrupter known as anexpulsion fuse, in which a usible link is placed inside an insulatingtube which is open to the atmosphere at one or both ends, and which uponoverload interrupts the circuit by the fusing of the link and the suddenexpulsive effect of the resultant arc inside the tube. It also relatesto similar circuit interrupters in which the circuit is opened insidethe tube by manual or electromagnetic means, instead of by thermalmeans.

Referring to the drawing, Fig. 1 shows a general view of an assembledunit embodying this invention; Figs. 2, 3 and 4 show in large scaledetails of the top latch in different positions; and Fig. 5 shows inperspective another position of these same parts.

The insulators I, are supported by any suitable hanger 2, and in turnthey support the forked bearing 3 and top fitting 4.

The latch hood 5 is pivoted at B and its travel in both directions islimited by the stop 1 on. the fitting 4.

'I'he tube 8 carries two trunnions 9 which are held by 3 and about whichthe tube pivots. 'Ihe swing end of the tube carries the fitting I towhich is pivoted the link II which in turn pivotally supports the latchI2. A fuse link I3 within the tube 8 completes the circuit between theline I4 and line I5. The screw I6 secures one end of the fuse link, andthe screw I'I together with the plate I8 hold the button head I9 whichis at .the other end of the link I3. Tension on the link I3 preventsrotation of the latch I2 about its double pivot at II.

When the tube is being closed in, the upper tip `of the latch I2 engageswith the tooth 5', thereby slightly rotating the hooded latch 5 aboutits pivot 6. The member I2 also pushes back the brush 24, and then 5drops down aided by the spring 26, so that the projection 5 engages andholds I2 in closed position as shown in Fig. 1. When upon overload thefuse ruptures and tension on I2 is released, the latch I2 disengagesfrom the tooth 5', andthe tube 8 falls by gravity to the position shownby dotted lines in Fig. 1.

On such equipment a low-amperage fuse-link is often used, and it isdesirable to prevent excessive strain upon this small link at all times.It is also advisable to protect moving joints from sleet which otherwisemight prevent proper operation. The hood 5 has an internal pivotalmounting at 6 and the lower flared edges of 5 tend to divert rain orsleet away from the parts beneath. Also the latch I2 has an internalpivotal 9, 1936, Serial No. 109,958 July 15, 1939 (Cl. G-116) mountingat I I, and thus further protection is given to this double-pivotedjoint.

The wide end 20 of the latch I2 serves as a shield to keep rain out ofthe top opening of the tube 8, and further protection is given by theiiange ZI on the tting I9, and by the projecting end 23 of the tube 8.The liange 22 nts between 2| and 23 and gives additional protectionagainst rain. When the fuse link has ruptured from overload, hot gasesare expelled upward from the tube 8, and the interlocking arrangement offlanges retards hot gases from the tube from eX- panding towards theinsulators, while allowing relatively free expansion away from theinsulators. Since these hot gases are conductive, this is desirable.

The iianges also allow a slight transverse motion of the double pivot atII. If .the fused tube when put into service is slammed hard against thebrush 24 and its stop 25, the parts assume the positions shown in Fig.2, with the flange 22 'bearing against the tube end 23, and taking theforce of the blow away from the fuse link.

Then if the tube 8 is pulled or bounces outwardly, the motion of I Iallows the other side of the flange 22 to be pressed against the flange2|, as shown in Fig. 3.

These members are usually castings, and their surfaces are slightlyrough, due to the sand mold. When the flanges are pressed together thereis considerable friction due to this roughness, and the rotation of thelatch I2 about its pivots at I I is thereby definitely retarded. Thisreduces the strain which is imposed on the link I3 under givenconditions. Another factor in the reduction of strain on the link I3 isthe fact that the tube 8 can move in or out somewhat while the latch I2remains still; this softens the hammerblow action of the tube 8. With asingle pivot I2 any counter-clockwise rotative strain on latch I2 wouldbe borne entirely by the fuse link I3, with no diminution due tofriction, and with all momentum of the tube 8 being applied to causerotation of the latch I2.

Furthermore, when the fuse link I3 has been ruptured, as by overload, avery slight rotative motion of I2 allows the iiange 22 to clear theflange 2 I, as in Fig. 4. Then as the tube 8 moves outwardly, the link II can drop downward with the latch I2, and so release the latch from 5',allowing the tube 8 to drop fully open.

There are various modications which can be made from the details as heredescribed without departing from the purpose and spirit of thisinvention.

projects, a latch member movably I claim:

1. In a circuit interruptor, in combination, two insulated supports, atubular container pivotally mounted upon one of said supports, a fusibleconductor within the container, and a Contact member connected to theswing end of ane container by a double-pivotal mounting, and a secondcontact member supported by the second insulated support and engageablewith the said rst Contact member.

2. InV a circuit interrupter, two gap-spaced insulated terminals, aninsulating tube with a ilexible conductor therein movable into and outof circuit closing position between the said two terminals, a contactmember to engage with one of said terminals and to hold the tube inclosed-circuit position, said contact member being connected tothe tubeby a double jointed pivotal mounting.

3. In a circuit interrupter, two gap-spaced insulated terminals, aninsulating tube with a iiexible conductor therein movable into and outof circuit closing position between the said two terminals, a Contactmember to engage with on'e of said terminals and to hold the tube inclosed-circuit position, said contact being connected to the tube by amovable link and two pivots.

4. In a circuit interrupter, two gap-spaced insulated terminals, aninsulating tube with a flein'ble conductor therein movable into and outof circuit-closing position between the said two terminals, a metallicfitting near the upper end. of the said tube from which the end of thetube attac-hed to the said fitting, said latch member and said f1ttingincluding interlocking barriers to modify the discharge of gases fromthe'end of the tube.

5. In a circuit interrupter, two gap-spaced insulated terminals, aninsulating tube with a iiexible conductor therein completing the circuitacross the said gap, one end of said tube being open for the dischargeof gases, a movable cap adjacent the said open end of the tube, togetherwith barriers adjacent the said cap and interlocked to retard the flowof any gas past the barriers.

6. In a circuit interrupter, two gap-spaced insulated terminals, aninsulating tube with a flexible conductor therein completing the circuitacross the said gap, one end of said tube being open for the dischargeof gases, a movable cap adjacent the said end of the tube, together withmeans stationary with the tube and adjacent to the cap to direct thedischarge of gases away, from the said insulated terminals.

7. In a circuit interrupter, two gap-spaced insulated terminals, aninsulating tube with a flexible conductor therein completing the circuitacross the said gap, one end of said tube being open for the dischargeof gases, a movable cap adjacent the said open end of the tube, togetherwith a barrier stationary with the tube and a coordinated barrier on thecap, operable to modify the discharge of gases from the said tube.

8. In a circuit interrupter, a pivotally mounted tubular container, afusible conductor within the container, a contact member mounted on thecontainer by a double pivoted hinge, said contact member being also aprotective shield for its own pivotal mounting.

9. In a circuit interrupter, two gap-spaced insulated terminals, aninsulating tube with a flexibleV conductor therein movable into and outof circuit closing position between the said two terminals, a metallicfitting near the upperend of the said tube, a latch member movablyattaohed to the said tting and forming a protectiver shield forV the endof the tube, Vsaid latch member and said ttin'g including coordinatedmeans to modify the discharge of gases from the tube.

G. N. LEMMON.

